"A riddle wrapped in a mystery inside an enigma": defining central auditory processing disorder

A. T. Cacace and D. J. McFarland (2005) define central auditory processing disorder (CAPD) as a "modality-specific perceptual dysfunction that is not due to peripheral hearing loss" and that "should be distinguishable from cognitive, language-based, and/or supramodal attentional problems" (p. 113). Although agreeing with the general thrust of their attempts to exclude supramodal causes of impaired auditory performance as being labeled CAPD, I argue that this definition suffers from a number of serious deficiencies. It is both too loose and too restrictive, excluding what might be low-level deficits that occur in more than one modality, at the same time including at least one form of modality-specific linguistic processing. I argue that any useful definition of CAPD must not only exclude supramodal causes of auditory deficits, but must be based on the notion of impaired brain function demonstrable for nonspeech sounds.